Problem: Solve for $x$ : $x - 20 = -6$
Answer: Add $20$ to both sides: $ \begin{eqnarray} \\ x - 20 &=& -6 \\ \\ {+20} && {+20} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-20 + x} &\hphantom{=}& \hphantom{-6} \\ x &=& -6 {+ 20} \\ \end{eqnarray} $ Simplify. $ x = 14$